1 /* 2 * 3 * Copyright (C) 2011 Novell Inc. 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 as published by 7 * the Free Software Foundation. 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/uuid.h> 12 #include "ovl_entry.h" 13 14 enum ovl_path_type { 15 __OVL_PATH_UPPER = (1 << 0), 16 __OVL_PATH_MERGE = (1 << 1), 17 __OVL_PATH_ORIGIN = (1 << 2), 18 }; 19 20 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) 21 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) 22 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN) 23 24 #define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay." 25 #define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque" 26 #define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect" 27 #define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin" 28 #define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure" 29 #define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink" 30 #define OVL_XATTR_UPPER OVL_XATTR_PREFIX "upper" 31 32 enum ovl_inode_flag { 33 /* Pure upper dir that may contain non pure upper entries */ 34 OVL_IMPURE, 35 /* Non-merge dir that may contain whiteout entries */ 36 OVL_WHITEOUTS, 37 OVL_INDEX, 38 }; 39 40 enum ovl_entry_flag { 41 OVL_E_UPPER_ALIAS, 42 OVL_E_OPAQUE, 43 OVL_E_CONNECTED, 44 }; 45 46 /* 47 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, 48 * where: 49 * origin.fh - exported file handle of the lower file 50 * origin.uuid - uuid of the lower filesystem 51 */ 52 #define OVL_FH_VERSION 0 53 #define OVL_FH_MAGIC 0xfb 54 55 /* CPU byte order required for fid decoding: */ 56 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) 57 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) 58 /* Is the real inode encoded in fid an upper inode? */ 59 #define OVL_FH_FLAG_PATH_UPPER (1 << 2) 60 61 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ 62 OVL_FH_FLAG_PATH_UPPER) 63 64 #if defined(__LITTLE_ENDIAN) 65 #define OVL_FH_FLAG_CPU_ENDIAN 0 66 #elif defined(__BIG_ENDIAN) 67 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN 68 #else 69 #error Endianness not defined 70 #endif 71 72 /* The type returned by overlay exportfs ops when encoding an ovl_fh handle */ 73 #define OVL_FILEID 0xfb 74 75 /* On-disk and in-memeory format for redirect by file handle */ 76 struct ovl_fh { 77 u8 version; /* 0 */ 78 u8 magic; /* 0xfb */ 79 u8 len; /* size of this header + size of fid */ 80 u8 flags; /* OVL_FH_FLAG_* */ 81 u8 type; /* fid_type of fid */ 82 uuid_t uuid; /* uuid of filesystem */ 83 u8 fid[0]; /* file identifier */ 84 } __packed; 85 86 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) 87 { 88 int err = vfs_rmdir(dir, dentry); 89 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 90 return err; 91 } 92 93 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry) 94 { 95 int err = vfs_unlink(dir, dentry, NULL); 96 pr_debug("unlink(%pd2) = %i\n", dentry, err); 97 return err; 98 } 99 100 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir, 101 struct dentry *new_dentry, bool debug) 102 { 103 int err = vfs_link(old_dentry, dir, new_dentry, NULL); 104 if (debug) { 105 pr_debug("link(%pd2, %pd2) = %i\n", 106 old_dentry, new_dentry, err); 107 } 108 return err; 109 } 110 111 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry, 112 umode_t mode, bool debug) 113 { 114 int err = vfs_create(dir, dentry, mode, true); 115 if (debug) 116 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 117 return err; 118 } 119 120 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry, 121 umode_t mode, bool debug) 122 { 123 int err = vfs_mkdir(dir, dentry, mode); 124 if (debug) 125 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); 126 return err; 127 } 128 129 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry, 130 umode_t mode, dev_t dev, bool debug) 131 { 132 int err = vfs_mknod(dir, dentry, mode, dev); 133 if (debug) { 134 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", 135 dentry, mode, dev, err); 136 } 137 return err; 138 } 139 140 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry, 141 const char *oldname, bool debug) 142 { 143 int err = vfs_symlink(dir, dentry, oldname); 144 if (debug) 145 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); 146 return err; 147 } 148 149 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name, 150 const void *value, size_t size, int flags) 151 { 152 int err = vfs_setxattr(dentry, name, value, size, flags); 153 pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n", 154 dentry, name, (int) size, (char *) value, flags, err); 155 return err; 156 } 157 158 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name) 159 { 160 int err = vfs_removexattr(dentry, name); 161 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); 162 return err; 163 } 164 165 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry, 166 struct inode *newdir, struct dentry *newdentry, 167 unsigned int flags) 168 { 169 int err; 170 171 pr_debug("rename(%pd2, %pd2, 0x%x)\n", 172 olddentry, newdentry, flags); 173 174 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags); 175 176 if (err) { 177 pr_debug("...rename(%pd2, %pd2, ...) = %i\n", 178 olddentry, newdentry, err); 179 } 180 return err; 181 } 182 183 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry) 184 { 185 int err = vfs_whiteout(dir, dentry); 186 pr_debug("whiteout(%pd2) = %i\n", dentry, err); 187 return err; 188 } 189 190 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode) 191 { 192 struct dentry *ret = vfs_tmpfile(dentry, mode, 0); 193 int err = PTR_ERR_OR_ZERO(ret); 194 195 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); 196 return ret; 197 } 198 199 /* util.c */ 200 int ovl_want_write(struct dentry *dentry); 201 void ovl_drop_write(struct dentry *dentry); 202 struct dentry *ovl_workdir(struct dentry *dentry); 203 const struct cred *ovl_override_creds(struct super_block *sb); 204 struct super_block *ovl_same_sb(struct super_block *sb); 205 int ovl_can_decode_fh(struct super_block *sb); 206 struct dentry *ovl_indexdir(struct super_block *sb); 207 bool ovl_index_all(struct super_block *sb); 208 bool ovl_verify_lower(struct super_block *sb); 209 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 210 bool ovl_dentry_remote(struct dentry *dentry); 211 bool ovl_dentry_weird(struct dentry *dentry); 212 enum ovl_path_type ovl_path_type(struct dentry *dentry); 213 void ovl_path_upper(struct dentry *dentry, struct path *path); 214 void ovl_path_lower(struct dentry *dentry, struct path *path); 215 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 216 struct dentry *ovl_dentry_upper(struct dentry *dentry); 217 struct dentry *ovl_dentry_lower(struct dentry *dentry); 218 struct ovl_layer *ovl_layer_lower(struct dentry *dentry); 219 struct dentry *ovl_dentry_real(struct dentry *dentry); 220 struct dentry *ovl_i_dentry_upper(struct inode *inode); 221 struct inode *ovl_inode_upper(struct inode *inode); 222 struct inode *ovl_inode_lower(struct inode *inode); 223 struct inode *ovl_inode_real(struct inode *inode); 224 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); 225 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); 226 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); 227 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); 228 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); 229 bool ovl_dentry_is_opaque(struct dentry *dentry); 230 bool ovl_dentry_is_whiteout(struct dentry *dentry); 231 void ovl_dentry_set_opaque(struct dentry *dentry); 232 bool ovl_dentry_has_upper_alias(struct dentry *dentry); 233 void ovl_dentry_set_upper_alias(struct dentry *dentry); 234 bool ovl_redirect_dir(struct super_block *sb); 235 const char *ovl_dentry_get_redirect(struct dentry *dentry); 236 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 237 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, 238 struct dentry *lowerdentry); 239 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); 240 void ovl_dentry_version_inc(struct dentry *dentry, bool impurity); 241 u64 ovl_dentry_version_get(struct dentry *dentry); 242 bool ovl_is_whiteout(struct dentry *dentry); 243 struct file *ovl_path_open(struct path *path, int flags); 244 int ovl_copy_up_start(struct dentry *dentry); 245 void ovl_copy_up_end(struct dentry *dentry); 246 bool ovl_check_origin_xattr(struct dentry *dentry); 247 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name); 248 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, 249 const char *name, const void *value, size_t size, 250 int xerr); 251 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 252 void ovl_set_flag(unsigned long flag, struct inode *inode); 253 void ovl_clear_flag(unsigned long flag, struct inode *inode); 254 bool ovl_test_flag(unsigned long flag, struct inode *inode); 255 bool ovl_inuse_trylock(struct dentry *dentry); 256 void ovl_inuse_unlock(struct dentry *dentry); 257 bool ovl_need_index(struct dentry *dentry); 258 int ovl_nlink_start(struct dentry *dentry, bool *locked); 259 void ovl_nlink_end(struct dentry *dentry, bool locked); 260 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); 261 262 static inline bool ovl_is_impuredir(struct dentry *dentry) 263 { 264 return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE); 265 } 266 267 static inline unsigned int ovl_xino_bits(struct super_block *sb) 268 { 269 struct ovl_fs *ofs = sb->s_fs_info; 270 271 return ofs->xino_bits; 272 } 273 274 275 /* namei.c */ 276 int ovl_check_fh_len(struct ovl_fh *fh, int fh_len); 277 struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt, 278 bool connected); 279 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, 280 struct dentry *upperdentry, struct ovl_path **stackp); 281 int ovl_verify_set_fh(struct dentry *dentry, const char *name, 282 struct dentry *real, bool is_upper, bool set); 283 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index); 284 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); 285 int ovl_get_index_name(struct dentry *origin, struct qstr *name); 286 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); 287 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, 288 struct dentry *origin, bool verify); 289 int ovl_path_next(int idx, struct dentry *dentry, struct path *path); 290 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 291 unsigned int flags); 292 bool ovl_lower_positive(struct dentry *dentry); 293 294 static inline int ovl_verify_origin(struct dentry *upper, 295 struct dentry *origin, bool set) 296 { 297 return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set); 298 } 299 300 static inline int ovl_verify_upper(struct dentry *index, 301 struct dentry *upper, bool set) 302 { 303 return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set); 304 } 305 306 /* readdir.c */ 307 extern const struct file_operations ovl_dir_operations; 308 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 309 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); 310 void ovl_cache_free(struct list_head *list); 311 void ovl_dir_cache_free(struct inode *inode); 312 int ovl_check_d_type_supported(struct path *realpath); 313 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, 314 struct dentry *dentry, int level); 315 int ovl_indexdir_cleanup(struct ovl_fs *ofs); 316 317 /* inode.c */ 318 int ovl_set_nlink_upper(struct dentry *dentry); 319 int ovl_set_nlink_lower(struct dentry *dentry); 320 unsigned int ovl_get_nlink(struct dentry *lowerdentry, 321 struct dentry *upperdentry, 322 unsigned int fallback); 323 int ovl_setattr(struct dentry *dentry, struct iattr *attr); 324 int ovl_getattr(const struct path *path, struct kstat *stat, 325 u32 request_mask, unsigned int flags); 326 int ovl_permission(struct inode *inode, int mask); 327 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, 328 const void *value, size_t size, int flags); 329 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, 330 void *value, size_t size); 331 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 332 struct posix_acl *ovl_get_acl(struct inode *inode, int type); 333 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags); 334 int ovl_update_time(struct inode *inode, struct timespec *ts, int flags); 335 bool ovl_is_private_xattr(const char *name); 336 337 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 338 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 339 bool is_upper); 340 struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry, 341 struct ovl_path *lowerpath, struct dentry *index, 342 unsigned int numlower); 343 static inline void ovl_copyattr(struct inode *from, struct inode *to) 344 { 345 to->i_uid = from->i_uid; 346 to->i_gid = from->i_gid; 347 to->i_mode = from->i_mode; 348 to->i_atime = from->i_atime; 349 to->i_mtime = from->i_mtime; 350 to->i_ctime = from->i_ctime; 351 } 352 353 /* dir.c */ 354 extern const struct inode_operations ovl_dir_inode_operations; 355 struct dentry *ovl_lookup_temp(struct dentry *workdir); 356 int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir, 357 struct dentry *dentry); 358 struct cattr { 359 dev_t rdev; 360 umode_t mode; 361 const char *link; 362 }; 363 int ovl_create_real(struct inode *dir, struct dentry *newdentry, 364 struct cattr *attr, 365 struct dentry *hardlink, bool debug); 366 int ovl_cleanup(struct inode *dir, struct dentry *dentry); 367 368 /* copy_up.c */ 369 int ovl_copy_up(struct dentry *dentry); 370 int ovl_copy_up_flags(struct dentry *dentry, int flags); 371 int ovl_copy_xattr(struct dentry *old, struct dentry *new); 372 int ovl_set_attr(struct dentry *upper, struct kstat *stat); 373 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper); 374 int ovl_set_origin(struct dentry *dentry, struct dentry *lower, 375 struct dentry *upper); 376 377 /* export.c */ 378 extern const struct export_operations ovl_export_operations; 379